Family Crossings doesn't seem to have an activity feed, so it can be difficult to determine what has been the lastest activity, especially if its a minor addition to the site like a comment on a gallery photo.
We noticed that after you upload multiple photos to a folder, you remain on the upload page instead of being directed back to the main gallery page. This was a little confusing.
FamilyCrossings.com does not have mobile support and because the layout of the home page has 4 columns, it may be difficult to use even on the landscape view of a table.
There are a minimum of 2-3 ads per page. When you first sign in their is a message asking you to click on one the Ads to support the site.
We couldn't find an option to have certain pages (ie a Family Reunion Info Page) public (doesn't require login).
We noticed a small bug - when you try to add an event at for example 2:00pm, it brings up the dailog for you to complete the event information but when you save it, it shows as a full day event.
Despite the opportunities for improvement listed above, Family Crossings has a good list of standard features and is worth considering if you don't need mobile support, public pages, or a unique url.